Radar Gun for chronographing

Does anyone have experience using a radar gun (not a hand held chrono) for on field testing. I know the PSP uses the stalker pro and it works great, however, 2000 is alot of money to spend. Does anyone have experience using something else. I see that bushnell makes a radar gun for about 100.00. It only goes up to 200 mph (about 298 fps) but my series is only a 270 fps limit.